Auto merge of #131213 - ismailarilik:handle-potential-query-instability-lint-for-rustc-resolve, r=<try>

Handle `rustc_resolve` cases of `rustc::potential_query_instability` lint

This PR removes `#![allow(rustc::potential_query_instability)]` line from [`compiler/rustc_resolve/src/lib.rs`](https://github.com/rust-lang/rust/blob/master/compiler/rustc_resolve/src/lib.rs#L12) and converts `FxHash{Map,Set}` types into `FxIndex{Map,Set}` to suppress lint errors.

A somewhat tracking issue: #84447

r? `@compiler-errors`

Author: bors

compiler/rustc_resolve/src/diagnostics.rs

@@ -1086,6 +1086,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                     this.add_module_candidates(module, &mut suggestions, filter_fn, None);
                 }
                 Scope::MacroUsePrelude => {
+                    // The suggestions are deterministically sorted at the bottom of this function.
+                    #[allow(rustc::potential_query_instability)]
                     suggestions.extend(this.macro_use_prelude.iter().filter_map(
                         |(name, binding)| {
                             let res = binding.res();
@@ -1104,6 +1106,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                     }
                 }
                 Scope::ExternPrelude => {
+                    // The suggestions are deterministically sorted at the bottom of this function.
+                    #[allow(rustc::potential_query_instability)]
                     suggestions.extend(this.extern_prelude.iter().filter_map(|(ident, _)| {
                         let res = Res::Def(DefKind::Mod, CRATE_DEF_ID.to_def_id());
                         filter_fn(res).then_some(TypoSuggestion::typo_from_ident(*ident, res))
@@ -1362,7 +1366,12 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         );
 
         if lookup_ident.span.at_least_rust_2018() {
-            for ident in self.extern_prelude.clone().into_keys() {
+            // `idents` is sorted before usage so ordering is not important here.
+            #[allow(rustc::potential_query_instability)]
+            let mut idents: Vec<_> = self.extern_prelude.clone().into_keys().collect();
+            idents.sort_by_key(|ident| ident.span);
+
+            for ident in idents {
                 if ident.span.from_expansion() {
                     // Idents are adjusted to the root context before being
                     // resolved in the extern prelude, so reporting this to the
@@ -1467,7 +1476,11 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             return;
         }
 
-        let unused_macro = self.unused_macros.iter().find_map(|(def_id, (_, unused_ident))| {
+        // Make ordering consistent before iteration
+        #[allow(rustc::potential_query_instability)]
+        let mut unused_macros: Vec<_> = self.unused_macros.iter().collect();
+        unused_macros.sort_by_key(|&(_, (key, _))| key);
+        let unused_macro = unused_macros.iter().find_map(|(def_id, (_, unused_ident))| {
             if unused_ident.name == ident.name { Some((def_id, unused_ident)) } else { None }
         });
 
@@ -1954,6 +1967,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         ident: Symbol,
         current_module: Module<'ra>,
     ) -> Option<Symbol> {
+        // The candidates are sorted just below.
+        #[allow(rustc::potential_query_instability)]
         let mut candidates = self
             .extern_prelude
             .keys()
@@ -2342,6 +2357,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         // Sort extern crate names in *reverse* order to get
         // 1) some consistent ordering for emitted diagnostics, and
         // 2) `std` suggestions before `core` suggestions.
+        #[allow(rustc::potential_query_instability)]
         let mut extern_crate_names =
             self.extern_prelude.keys().map(|ident| ident.name).collect::<Vec<_>>();
         extern_crate_names.sort_by(|a, b| b.as_str().partial_cmp(a.as_str()).unwrap());
@@ -2839,6 +2855,8 @@ fn show_candidates(
             } else {
                 // Get the unique item kinds and if there's only one, we use the right kind name
                 // instead of the more generic "items".
+                // Ordering is not important if there's only one element in the set.
+                #[allow(rustc::potential_query_instability)]
                 let mut kinds = accessible_path_strings
                     .iter()
                     .map(|(_, descr, _, _, _)| *descr)

compiler/rustc_resolve/src/imports.rs

@@ -4,7 +4,7 @@ use std::cell::Cell;
 use std::mem;
 
 use rustc_ast::NodeId;
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
 use rustc_data_structures::intern::Interned;
 use rustc_errors::codes::*;
 use rustc_errors::{Applicability, MultiSpan, pluralize, struct_span_code_err};
@@ -220,7 +220,7 @@ impl<'ra> ImportData<'ra> {
 pub(crate) struct NameResolution<'ra> {
     /// Single imports that may define the name in the namespace.
     /// Imports are arena-allocated, so it's ok to use pointers as keys.
-    pub single_imports: FxHashSet<Import<'ra>>,
+    pub single_imports: FxIndexSet<Import<'ra>>,
     /// The least shadowable known binding for this name, or None if there are no known bindings.
     pub binding: Option<NameBinding<'ra>>,
     pub shadowed_glob: Option<NameBinding<'ra>>,
@@ -482,7 +482,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                 let key = BindingKey::new(target, ns);
                 let _ = this.try_define(import.parent_scope.module, key, dummy_binding, false);
                 this.update_resolution(import.parent_scope.module, key, false, |_, resolution| {
-                    resolution.single_imports.remove(&import);
+                    resolution.single_imports.swap_remove(&import);
                 })
             });
             self.record_use(target, dummy_binding, Used::Other);
@@ -837,7 +837,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                         }
                         let key = BindingKey::new(target, ns);
                         this.update_resolution(parent, key, false, |_, resolution| {
-                            resolution.single_imports.remove(&import);
+                            resolution.single_imports.swap_remove(&import);
                         });
                     }
                 }

compiler/rustc_resolve/src/late.rs

@@ -44,8 +44,6 @@ mod diagnostics;
 
 type Res = def::Res<NodeId>;
 
-type IdentMap<T> = FxHashMap<Ident, T>;
-
 use diagnostics::{ElisionFnParameter, LifetimeElisionCandidate, MissingLifetime};
 
 #[derive(Copy, Clone, Debug)]
@@ -261,7 +259,7 @@ impl RibKind<'_> {
 /// resolving, the name is looked up from inside out.
 #[derive(Debug)]
 pub(crate) struct Rib<'ra, R = Res> {
-    pub bindings: IdentMap<R>,
+    pub bindings: FxIndexMap<Ident, R>,
     pub kind: RibKind<'ra>,
 }
 
@@ -1536,7 +1534,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                         // Allow all following defaults to refer to this type parameter.
                         forward_ty_ban_rib
                             .bindings
-                            .remove(&Ident::with_dummy_span(param.ident.name));
+                            .swap_remove(&Ident::with_dummy_span(param.ident.name));
                     }
                     GenericParamKind::Const { ref ty, kw_span: _, ref default } => {
                         // Const parameters can't have param bounds.
@@ -1564,7 +1562,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                         // Allow all following defaults to refer to this const parameter.
                         forward_const_ban_rib
                             .bindings
-                            .remove(&Ident::with_dummy_span(param.ident.name));
+                            .swap_remove(&Ident::with_dummy_span(param.ident.name));
                     }
                 }
             }
@@ -2246,6 +2244,8 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                         }
                     }));
                 }
+                // Ordering is not important if there's only one element in the set.
+                #[allow(rustc::potential_query_instability)]
                 let mut distinct_iter = distinct.into_iter();
                 if let Some(res) = distinct_iter.next() {
                     match elision_lifetime {
@@ -3854,7 +3854,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
         }
     }
 
-    fn innermost_rib_bindings(&mut self, ns: Namespace) -> &mut IdentMap<Res> {
+    fn innermost_rib_bindings(&mut self, ns: Namespace) -> &mut FxIndexMap<Ident, Res> {
         &mut self.ribs[ns].last_mut().unwrap().bindings
     }
 
@@ -5008,7 +5008,12 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         let mut late_resolution_visitor = LateResolutionVisitor::new(self);
         late_resolution_visitor.resolve_doc_links(&krate.attrs, MaybeExported::Ok(CRATE_NODE_ID));
         visit::walk_crate(&mut late_resolution_visitor, krate);
-        for (id, span) in late_resolution_visitor.diag_metadata.unused_labels.iter() {
+        // Make ordering consistent before iteration
+        #[allow(rustc::potential_query_instability)]
+        let mut unused_labels: Vec<_> =
+            late_resolution_visitor.diag_metadata.unused_labels.iter().collect();
+        unused_labels.sort_by_key(|&(key, _)| key);
+        for (id, span) in unused_labels {
             self.lint_buffer.buffer_lint(
                 lint::builtin::UNUSED_LABELS,
                 *id,

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -1957,6 +1957,8 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
         let Some(default_trait) = default_trait else {
             return;
         };
+        // The ordering is not important because `any` is used on the iterator.
+        #[allow(rustc::potential_query_instability)]
         if self
             .r
             .extern_crate_map
@@ -2195,6 +2197,8 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
                         // Items from the prelude
                         if !module.no_implicit_prelude {
                             let extern_prelude = self.r.extern_prelude.clone();
+                            // The names are sorted at the bottom of this function.
+                            #[allow(rustc::potential_query_instability)]
                             names.extend(extern_prelude.iter().flat_map(|(ident, _)| {
                                 self.r
                                     .crate_loader(|c| c.maybe_process_path_extern(ident.name))

compiler/rustc_resolve/src/lib.rs

@@ -9,7 +9,6 @@
 // tidy-alphabetical-start
 #![allow(internal_features)]
 #![allow(rustc::diagnostic_outside_of_impl)]
-#![allow(rustc::potential_query_instability)]
 #![allow(rustc::untranslatable_diagnostic)]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![doc(rust_logo)]

compiler/rustc_resolve/src/macros.rs

@@ -346,7 +346,11 @@ impl<'ra, 'tcx> ResolverExpand for Resolver<'ra, 'tcx> {
     }
 
     fn check_unused_macros(&mut self) {
-        for (_, &(node_id, ident)) in self.unused_macros.iter() {
+        // Make ordering consistent before iteration
+        #[allow(rustc::potential_query_instability)]
+        let mut unused_macros: Vec<_> = self.unused_macros.iter().collect();
+        unused_macros.sort_by_key(|&(_, (key, _))| key);
+        for (_, &(node_id, ident)) in unused_macros {
             self.lint_buffer.buffer_lint(
                 UNUSED_MACROS,
                 node_id,
@@ -356,6 +360,8 @@ impl<'ra, 'tcx> ResolverExpand for Resolver<'ra, 'tcx> {
         }
 
         for (&def_id, unused_arms) in self.unused_macro_rules.iter() {
+            // It is already sorted below.
+            #[allow(rustc::potential_query_instability)]
             let mut unused_arms = unused_arms.iter().collect::<Vec<_>>();
             unused_arms.sort_by_key(|&(&arm_i, _)| arm_i);